1. Flat kinematics

In general kinematics, we discussed (see article General kinematics) ) a special category of solid motion: planar motion.

If we consider two solids (S ₁ ) and (S ₂ ) having such a motion, each point of (S ₂ ) moves in a plane of (S ₁ ). There are infinitely many planes of (S ₂ ) that remain in coincidence. We have thus seen (cf. article General kinematics ) that the study of such motions reduces to the study of a plane (P ₂ ) related to (S ₂ ) and which remains coincident with a plane (P _1...